Codeforces 715B Complete The Graph(dijkstra+heap)

n点m边的图，有些边权值是0，让你把所有的0权改成正整数，能否s到t最短路是L
n1000，m10000，开头想着直接搜一边就搞出来，结果一直wa，其实这题的数据范围
O(nmlogn)都能过，所以直接暴力一点就好了，很巧妙的贪心未必是正确的
把所有的0权边去掉，跑一次，如果最短路小于L，NO
然后一条一条往里面加，并且权值是1，如果最短路小于等于L，那么就把这条改成L−dis[t]+1
如果最后全加完了，最短路都大于L，NO
一条一条加，保证肯定能满足情况，并且cf上也跑得过
以后还是得多看数据范围啊

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代码：

#include <map>#include <set>#include <stack>#include <queue>#include <cmath>#include <string>#include <vector>#include <cstdio>#include <cctype>#include <cstring>#include <sstream>#include <cstdlib>#include <iostream>#include <algorithm>#pragma comment(linker, "/STACK:102400000,102400000")using namespace std;#define   MAX           100005#define   MAXN          6005#define   maxnode       15#define   sigma_size    30#define   lson          l,m,rt<<1#define   rson          m+1,r,rt<<1|1#define   lrt           rt<<1#define   rrt           rt<<1|1#define   middle        int m=(r+l)>>1#define   LL            long long#define   ull           unsigned long long#define   mem(x,v)      memset(x,v,sizeof(x))#define   lowbit(x)     (x&-x)#define   pii           pair<int,int>#define   bits(a)       __builtin_popcount(a)#define   mk            make_pair#define   limit         10000//const int    prime = 999983;const int    INF   = 0x3f3f3f3f;const LL     INFF  = 0x3f3f;const double pi    = acos(-1.0);//const double inf   = 1e18;const double eps   = 1e-8;const LL     mod   = 1e9+7;const ull    mx    = 133333331;/*****************************************************/inline void RI(int &x) {    char c;    while((c=getchar())<'0' || c>'9');    x=c-'0';    while((c=getchar())>='0' && c<='9') x=(x<<3)+(x<<1)+c-'0'; }/*****************************************************/struct Edge{    int u,v,next,c;}edge[MAX],e[MAX];int head[MAX];LL dis[MAX];int vis[MAX];int tot;int n;int L;void init(){    mem(head,-1);    tot=0;}void add_edge(int a,int b,int c){    edge[tot]=(Edge){a,b,head[a],c};    head[a]=tot++;}LL spfa(int s,int t){    for(int i=0;i<n;i++) dis[i]=1e18;    mem(vis,0);    queue<int> q;    q.push(s);    dis[s]=0;    vis[s]=1;    while(!q.empty()){        int u=q.front();q.pop();        vis[u]=0;        for(int i=head[u];i!=-1;i=edge[i].next){            int v=edge[i].v;            if(dis[v]>dis[u]+edge[i].c){                dis[v]=dis[u]+edge[i].c;                if(!vis[v]){                    vis[v]=1;                    q.push(v);                }            }        }    }    return dis[t];}struct Node{    int id,val;    bool operator<(const Node &a)const{        return val>a.val;    }}x;LL dijkstra(int s,int t){    priority_queue<Node> q;    for(int i=0;i<n;i++) dis[i]=1e18;    mem(vis,0);    x=(Node){s,0};    dis[s]=0;    q.push(x);    while(!q.empty()){        x=q.top();        q.pop();        int u=x.id;        if(vis[u]) continue;        vis[u]=1;        for(int i=head[u];i!=-1;i=edge[i].next){            int v=edge[i].v;            if(!vis[v]&&dis[v]>dis[u]+edge[i].c){                dis[v]=dis[u]+edge[i].c;                q.push((Node){v,dis[v]});            }        }    }    return dis[t];}int main(){    int m,s,t;    while(cin>>n>>m>>L>>s>>t){        init();        int num=0;        for(int i=0;i<m;i++){            int a,b,c;            scanf("%d%d%d",&a,&b,&c);            if(c){                add_edge(a,b,c);                add_edge(b,a,c);            }            e[i]=(Edge){a,b,0,c};        }        if(spfa(s,t)<L){            printf("NO\n");            continue;        }        for(int i=0;i<m;i++){            if(e[i].c) continue;            add_edge(e[i].u,e[i].v,1);            add_edge(e[i].v,e[i].u,1);            e[i].c=1;            LL tmp=dijkstra(s,t);            if(tmp<L){                e[i].c=(L-(tmp-1));                edge[tot-1].c=e[i].c;                edge[tot-2].c=e[i].c;            }         }        if(dijkstra(s,t)>L){            printf("NO\n");            continue;        }        cout<<"YES"<<endl;        for(int i=0;i<m;i++){            printf("%d %d %d\n",e[i].u,e[i].v,e[i].c);        }    }    return 0;}